Vehicles are generally equipped with a parking brake system for keeping the vehicle motionless when it is parked. The traditional parking brake system is hand-operated and thus named “handbrake”. In order to start a car equipped with the handbrake on a slope, the driver needs to manually release the handbrake and, at the same time, operate the accelerator and clutch. The handbrake-equipped car requires the driver to have a high driving skill.
With the development of technology, electric parking brake (EPB) systems have been gradually replacing the traditional manually operated handbrakes. The existing EPB system includes an electric actuator which drives calipers and brake pads to brake the car. The actuator usually includes a motor for providing the driving force and a speed-reduction transmission mechanism through which the high speed rotation of the motor is greatly decreased and the torque is increased. A typical speed-reduction transmission mechanism includes components such as worms and worm wheels, gears and transmission belts. The transmission belt, which can prevent the transmission of vibrations between the components connected at opposite ends of the belt thus reducing noises, are widely used in the actuators of vehicles. However, vibrations of components, such as the motor, in the actuator can still be transmitted outwards through other peripheral components. As a result, the actuator still generates a certain level of noise during operation.
Hence there is a desire for an actuator for an electric parking brake system which can effectively reduce noise.